Many of my plants just aren't very full even after years, and some even look stunted. Last year I had poor flowering on several mature plants that should have been much showier.
The Rose of Sharon bloomed sparsely, and the butterfly bushes weren't great. The caryopteris in front (in too much shade?) looked skimpy.
Major Wheeler honeysuckle (also in too much shade perhaps) didn't produce much and I never even got a photo of it last spring.
The Venosa violacae clematis has always been spindly and it produces only a few blooms, even after six years in my garden.
Other plants were better -- the Cascade rose and the Kintzley's Ghost plants flowered well enough. The peony is okay, it had brief blooms. Sweet Summer Love clematis bloomed well.
I did rejuvenate prune the caryopteris and butterfly bushes this winter.
I used bloom booster fertilizer on most everything last year: water soluble fast acting Tiger Bloom 2-8-4 and Jack's 10-30-20, both lower nitrogen fertilizers with higher phosphorous. New Mexico soils are usually ok for potassium but the phosphorus is locked up and often unavailable.
Nitrogen contributes to overall growth and foliage.
Phosphorous supports roots and blooms.
Potassium assures disease resistance and hardiness.
Bloom booster fertilizing helped some things look a bit better, but I didn't notice greater flower production on anything.
I do notice when I dig up a newer plant or a struggler the root development is always very poor. And it takes three or four years for my new plantings to grow at all.
So here is my 3 prong approach to getting plants better established, growing bigger and putting out more flowers:
1. Mycorrhizae fungus - a powder diluted in water and applied as a soil drench. The fungi drench has to reach and touch the roots. I only got two one pound bags, not very much. I'll experiment with using it a couple times in the season on the smallest strugglers:
The potted cuphea
Electric Blue penstemon
Orange Kudos agastaches
The tiny sulphur buckwheats
Annuals (zinnias), applied directly to roots at potting time
And all the new plants I just ordered, applied at planting time
2. Rose Tone - a standard granular NPK 4-3-2 fertilizer for growth and flowering. I got a 4 pound bag. I'll use it on:
The Venosa violacae clematis
Sweet Sumer Love clematis
Red Cascade rose
Container plants, including Kent's Beauty oregano
3. Dr. Earth Exotic Blend (for hibiscus) granular fertilizer. It is highest in potassium, low in phosphorous, with medium nitrogen. NPK 5-4-6. I'll use it on:
The Rose of Sharon
Delphiniums
Most sources give generic plant advice for Rose of Sharon to apply a balanced fertilizer 10-10-10 and add compost. But a couple sources have said that hibiscus, both the tropical and the hardy althea, want higher potassium. So I'll try it.
Also, the delphiniums in the dining room window garden apparently can use higher potassium, so I'll try it on them too.
The caryopteris and Major Wheeler honeysuckle need more sun, though.
(Yes, I should get a soil test done. The extension office is nearby at the fairgrounds, easy to get to. I just need to get the forms and dig up the dirt to do the test. But the test doesn't address a specific plant's need, like that of hibiscus needing higher potassium than most plants, does it?)
Why doesn't mine look like this, planted at Newman's parking lot ---